The assays currently used to detect infection with the HIV virus (which is responsible for AIDS) are cumbersome and slow. They involve multistep processes which require significant technical support and hours or days to complete. We propose to construct a microfabricated immunosensor which can directly detect antibodies against HIV virus in small volumes of serum within a few minutes. Two types of sensors will be examined: a capacitance-based gold (or gold on silicon) electrode, and a fiber optic fluorescent sensor. In prior work we have synthesized and purified a 21 amino acid peptide which is a major HIV antigen, and have developed methods for coupling the peptide to both gold and glass surfaces. We have also raised antibodies against this peptide. We now propose to determine whether antibody binding can be demonstrated to the sensor-bound antigen and whether capacitance of fluorescent changes can be observed when such binding occurs. We also propose new methods for antigen attachment to the sensors which will reduce steric problems which may occur with close-packed antigen monolayers, and the development of fluorescent chemical crosslinkers and antigens. When a responding sensor is developed, we will examine the response to the HIV antibodies present in blood of individuals with AIDS. All of the methods and procedures for this project have been described in the literature, including immunosensors which are very similar in design. Thus, no development of new technology or methods is required. This is a multidisciplinary undertaking; the preparation and engineering of the electronic sensors will be done in the Electronics Design Center (CWRU); the fiber optic sensors will be constructed in the Fiber Optic Sensor Group at John Carroll University; the chemistry and biochemistry will be done in the chemistry and biochemistry departments at CWRU; and the testing of the AIDS sera in the HIV Serology Labs at the Cleveland Clinic.